NEW YORK — Bill Clinton thumped Mitt Romney as dangerous for the country Monday night, telling donors who ponied up thousands of dollars to see him paired with President Barack Obama that the presumptive Republican nominee and his policies would be “calamitous.”

The former president made the remarks just days after he pierced Chicago’s chief line of attack against Romney by praising the Republican’s business record as “sterling.” On Monday night, Clinton seemed determined to plow past it — never referencing the stray words and instead focusing on the implications of a Romney administration.

The events were part of a trio of fundraisers that the former president held for Obama on Monday night here, taking place in a private home, the Waldorf Astoria hotel and the New Amsterdam Theatre in Times Square.

Obama himself stuck to his standard stump speech throughout much of the night — though the most interesting moment came in the final event of three, when the president slipped and called his rival “George Romney” — the name of the GOP standard-bearer’s father, a man who ran for president during the era now chronicled on “Mad Men,” the show a top Obama adviser has used to described Mitt Romney and his policies as throwbacks.

“Governor Romney… has had great success in his life and he’s raised a beautiful family,” Obama said quickly, correcting himself as the crowd laughed loudly. “But he has a theory about the economy that basically says, if I’m maximizing returns for my investors, for wealthy individuals like myself, then everybody’s going to be better off.”

Referring to Romney, Clinton told a group of well-heeled donors at the home of financier Marc Lasry that “the alternative would be in my opinion calamitous for our country and the world.” Obama, he added, has the “right economic policy and the right political approach and I think that their economics are wrong-headed and their politics are worse.”

It was a theme that Clinton continued at a Broadway theater event, where he joked about serving as the warm-up act for Obama.

The former president has stumped hard for Obama four years after the 44th president bested his wife, Hillary Clinton, for the Democratic nomination. And the once-raw wounds that were publicly clear have healed. But Clinton’s remarks last week about Romney’s time at Bain Capital — it was “good work,” Clinton said — underscore that he is not a controllable surrogate, to the chagrin of Obama backers.

Clinton undoubtedly believes what he said about Romney’s business tenure, given the centrist path the former president took the party in the 1990s (although some Democrats privately argued Clinton is mindful that his wife might have an easier path, should she run again, without having to come after two Democratic terms).

Yet while some Obama supporters were frustrated with Clinton’s comments last week — they are almost guaranteed to end up in a Romney response ad on the Bain attacks — they kept the bickering to a minimum, in part out of the reality that the former president’s campaign skills and connection to the “Hillary voters” who still elude the current president are crucial right now.

Clinton’s ability to distill the message that Democrats are trying to deliver — that Obama came into office under extraordinary circumstances, and that Romney would be a risk — were on display Monday night.

“I know that things are not perfect now,” Clinton told the crowd. “I know they’re a little slow now but let me just remind you …in the month he took the oath of office we lost 800,000 jobs.”

On health care reform, Clinton said, “They tell you how terrible this health care bill is … it’s hard for them since Gov. Romney’s finest act as governor was to sign a bill with the individual mandate in it which he has now renounced.”

“I could give you 50 more things,” said Clinton. He denounced Republicans for embracing “policies of the eurozone.”

Obama, he said, “did the best he could with a lousy hand.”

“I don’t think it’s important to reelect the president, I think it is essential to reelect the president,” Clinton said in a notes-less speech.

At an earlier event, Clinton struck similar themes, saying, Obama came into power “under unimaginably difficult circumstances … it is my opinion that he has performed extremely well under very, very difficult circumstances.”

Clinton suggested Obama had tried working with a recalcitrant Congress. Obama, he added, has “had to get all this done while people as recently as last week were still saying he wasn’t born in America. He’s had to get all this done with a House of Representatives that had one of the tea party members claim that 78 to 81 members of the Democratic Caucus were members of the Communist Party. And neither the Republican nominee nor other Republican leaders rebuked him for saying that.”

And: “This is not the 1950s! At least Joe McCarthy could skate on the premise that there were still one or two living communists walking around. Nobody’s seen a communist in over a decade!”

At the Broadway event, Obama rapped Republicans and Romney’s side, saying, “There’s no vision for the future there, no imagination.”

He added, “Folks are still hurting, and this has been a long slog for people… That’s compounded by $500 million in super PAC negative ads [that will run] over the course of the next five months, that will try to feed all those fears, those anxieties and that frustration. That’s basically the argument that the other side is making. They’re not offering anything new, they’re just saying, things are tough, it’s Obama’s fault!”

At the events, Obama also acknowledged Hillary Clinton, saying that the country’s foreign relations are strong right now because of his secretary of state. Bill Clinton, sitting on a stool onstage, clapped as he said it.

Obama, whose calling card of late has been a strong personal popularity figure that dwarfs his job approval number, tried to recall the 2008 race for the crowd, saying, “It’s gonna be a tough election. But 2008 was tough too.”

Obama added, “I’m more determined than I’ve ever been to finish what we’ve started. I’m not a perfect man and haven’t been and won’t be a perfect president, nobody is. But what I told you was I’d always tell you what I thought, I’d always tell you where I stood … I’ve kept that promise, Broadway.”